The present invention relates to a socket that electrically connects an integrated circuit with an IC board. More particularly, the present invention is directed to a socket, such as those used for testing or connecting an integrated circuit, that incorporates an array of two-piece connectors that achieve a positive connection between an IC device under test (DUT) and a board, such as a load board of a piece of test equipment or other fixture.
Integrated circuit tester devices have long been used in the semiconductor industry to test and evaluate the quality of the chips off the manufacturing line. Signal integrity is a critical aspect of chip design and testing. To this end, it is desirable to maintain impedance through a conducting portion of a contact interconnecting the integrated circuit lead to its corresponding load board pad at a particular desired level. The effective impedance of the design is a function of a number of factors. These include width and length of conduction path, material of which the conductive structure is made, material thickness, etc.
When testing the electrical characteristics of a packaged or molded semiconductor device such as an integrated circuit (IC), it is common to utilize a specialized test socket that secures and connects the IC to the equipment that evaluates its performance, i.e. a load board. Many different test sockets have been devised for quickly and temporarily connecting integrated circuit leads of a chip to be tested to a load board of a tester. Automated test apparatus in particular use a number of such sockets. Typical socket arrangements use force brought to bear upon a contact positioned between a lead of the IC and the load board to deform a probe tip of the contact and engage a pad on the load board. Such a configuration provides for positive connection between the pins or contact pads of the DUT and corresponding leads of a test apparatus. Examples of this type of connection can be found, for example, in U.S. Pat. No. 6,409,521 to Rathburn, and U.S. Pat. No. 7,737,708 to Sherry, the teachings and contents of both of which are fully incorporated herein by reference.
Whether it is for testing integrated circuits or for mounting such circuits on a board, appropriate socket-like connectors are needed. Factors such as cost, having a low profile, and shortening the electrical signal path drive the industry to constantly seek to improve on the prior art sockets. A solution to the foregoing was provided by U.S. Pat. No. 7,918,669 to Tiengtum, and assigned to the present assignee, the contents of which are fully incorporated herein by reference. A feature of that device was a cylindrical elastomer that provided a resilient biasing of the connectors, which allowed the testing device to reliably make effective contact with the device under test (DUT). This cylindrical elastomer, however, wears quickly and begins to deform after multiple uses, reducing its effectiveness. Once it begins to wear, it can twist, which leads to further wear and loss of resiliency. This leads to an issue with the connector establishing reliable contact under certain conditions. The present invention addresses those issues.